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A Study of TAK-503 in Children and Teenagers With Attention Deficit Hyperactivity Disorder (ADHD)

NCT04085172 · Status: COMPLETED · Phase: PHASE4 · Type: INTERVENTIONAL · Enrollment: 396

Last updated 2026-04-13

Study results available
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Summary

The main aim of this study is learn more about long-term TAK-503 treatment in children and teenagers with ADHD for whom earlier stimulant treatment did not work.

The study has two parts (A and B). In Part A, participants will take tablets of TAK-503, atomoxetine or placebo and in Part B TAK-503 tablets.

Conditions

  • Attention Deficit Hyperactivity Disorder

Interventions

DRUG

Guanfacine hydrochloride (TAK-503)

Participants aged 6 to 12 years will receive a dose of 1 to 4 mg and aged 13 to 17 years will receive a dose of 5 to 7 mg TAK-503 oral tablets once daily for 18 weeks in Part A or 52 weeks in Part B.

DRUG

Atomoxetine hydrochloride

Participants will receive Atomoxetine hydrochloride oral capsule once daily for 18 weeks in Part A.

OTHER

Placebo

Participants aged 6 to 12 years will receive a dose of 1 to 4 mg and aged 13 to 17 years will receive a dose of 5 to 7 mg placebo matched to TAK 503 oral tablets once daily for 18 weeks and placebo matched to atomoxetine hydrochloride oral capsules at once daily for 18 weeks in Part A.

Sponsors & Collaborators

  • Takeda Development Center Americas, Inc.

    collaborator INDUSTRY

  • Shire

    lead INDUSTRY

Principal Investigators

  • Study Director · Takeda Development Center Americas

Study Design

Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Model
PARALLEL

Eligibility

Min Age
6 Years
Max Age
17 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2019-09-18
Primary Completion
2025-09-02
Completion
2025-09-02
FDA Drug
Yes

Countries

  • United States
  • Austria
  • Belgium
  • Germany
  • Netherlands
  • Portugal
  • Spain
  • Sweden
  • United Kingdom

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT04085172 on ClinicalTrials.gov